Front Med (Lausanne). 2026 Jun 24;13:1871508. doi: 10.3389/fmed.2026.1871508. eCollection 2026.
ABSTRACT
BACKGROUND: Persistent deficits in periarticular muscle strength and functional performance are commonly observed following anterior cruciate ligament reconstruction, potentially compromising long-term knee joint health. As a key non-pharmacologic rehabilitation strategy, strengthening exercise is widely implemented to address these impairments. However, evidence regarding its effects on knee muscle strength and hop-performance outcomes remains inconsistent. Therefore, this study aimed to systematically quantify the effects of strengthening exercise on knee muscle strength and hop performance after ACLR using a three-level meta-analytic approach.
METHODS: PubMed, Web of Science, Embase, Cochrane Library, and SPORTDiscus were searched through January 6, 2026. Randomized controlled trials examining strengthening-based rehabilitation after ACLR were included. Standardized mean differences (Hedges’ g) were calculated from pre-post change scores. Three-level multivariate random-effects meta-analyses were conducted, with moderator analyses examining postoperative time, population type, and assessment time point. Risk of bias was assessed using RoB 2, and publication bias was explored via funnel plots and Egger’s regression.
RESULTS: Nine trials were included, contributing a total of 24 effect sizes across outcomes. Strengthening exercise significantly improved knee muscle strength (d = 0.39, 95% CI 0.01-0.77, p = 0.046, I 2 = 55.8%). No significant effect was found for hop performance (d = -0.03, 95% CI – 0.54 to 0.48, p = 0.906, I 2 = 77.8%). No statistically significant moderation effects of postoperative time, population type, or assessment time point were detected for either outcome.
CONCLUSION: Strength-oriented rehabilitation interventions appear to improve knee muscle strength following ACL reconstruction, whereas no significant overall effect was observed for hop performance. Comprehensive rehabilitation strategies addressing neuromuscular and functional demands may be required to optimize postoperative recovery.
PMID:42422842 | PMC:PMC13341512 | DOI:10.3389/fmed.2026.1871508
